Process for producing ionones



chi

Patented Apr. 2 193 5 Q .9 t 1 2 rRoo ss FOR, PRODUCING IOl N'ONE S ware Walter Christian Meuly, New Brunswick, N. I

assignor to I. du Pont de Nemours & Company, Wilmington, 1)el., a corporation ofDela- No .Drawing; 1 Application August 35; 1933,

l invention relates to methods for the isomerization' of iononev and its alkyl derivatives.

In the past-ionones havebeen produced by reacting -citral with' a methyl-alkyl-ketone. The

'pseudo-ionone produced thereby was then isomerized by treatment with acids, oracid salts of ,polybasicacidsp German Patent No. 73,089- describes theuse' ofrdilute acids, such as sulfuric acid, at boiling temperature for this purpose;

German Patent-No. 129,027 mentions that mineral acids and some ofthe stronger-organic acids may be employed in this connection; German Patent No. 138,939states that mono-sodium-sulfa'temay be used, and gives instructions whereby the conditions of thereaction are so regulated that this compound decomposes into a mixture of-sulfuricacid and sodium sulfate. This patentalso describes the use of ferric chloride, which liberates hydrochloric acid by hydrolysis; German-Patent No. 157,647mentions the .possibilityof using neutral salts which do not split on acids on'heatingi: Calcium chloride, magnesium sulfate and sodium acetate are described herein, the reaction being carried out at high temperatures in; an

autoclave, and alcohol being used as a solvent. It haslheretofore been verydiflicult to obtain good yields of ionones due to side reactions which result in the/production of deleterious contam-' inantssuch as resins. These .prior art methods were also defectivein'that theflacids used were I ingeneral quite expensive, and their removal from V the product requiredtediousextractions ordilu-. tionsand reconcentrations. Furthermore, the ex-. tremely corrosive action of the acids as well as 5'; the high temperaturesnecessitated the .useof ex-fpensive equipment. l g It is an object of this invention to obtain high yields of ionones of excellent purity; A further object is to produce isomerization by means of relatively cheap and readily available isomeriz'-- ing media. A still further object is tofldevelop a process which eliminates the necessity ofusingf.

expensive equipment, as well the tedious methods of separating the product from the.

isomerizing media previously ;used. An" additional object is to perfect a process which may be readily; controlled, and ,which'does not require highly skilled workers for its operation. Additional objects will become apparent from a consideration of the following description. Y

These objects are' attained according. to the herein described invention, wherein pseudoionones are treated with an aqueous solution of zinc iodide, zinc bromide, and/or zincchloride.

This treatment is preferably carriedout at atmospheric pressure and at temperatures which are sufficiently elevatedto cause; the solutionto re- I'I'he invention may be more completely under stood byreference "to: the following illustrative examplesfin .which the quantities are stated in parts byweight: I

" T Example 1 v,

100 parts of zinc bromide were dissolved in 50 10 parts of water. The concentrated aqueous solution thus obtained contained: about 67 of zinc bromide and under atmospheric pressure ithad a boiling *pointof 115 C; Undervigorous agitation 50 parts of vpseudo-iono-ne (boiling point place. The progress of the isomerization may be 5 followed by removing small samples from the reaction mass; washing free from zinc bromide'and' measuring the refractive index of the oil. In thecourse of one hour n had dropped fromthe original 1.5320 to about 1.5160; After another ,half-hourstime n20 was'about 1.5130 and thereafter it began to gradually rise, indicating that thefisomerizationfwas completed and thatresinification was beginning to take place. a l

' :After about bneand one-half hours the reaction'mass was cooled toroom temperature. The

oil separated on top ofthe zinc bromide solution and was easily removed therefrom. The zinc bromide solution'remained unchanged "and used to isomerize fresh quantities offps'eudow 40.:

ionone. The crude ionone was Washed free from zinc bromide by'shaking with water. tional distillation under reduced pressure the} crude product was freed from a small amountof v 1 The pure terpenes and from some residue. ionone obtained boiled at -85? at'2.5 m/n'i" Hg pressure zand wasa mixture'of alphaand beta ionone. in -.'wmch the. alpha-isomer was' slightly dominant. .Yield, about i 1 l I Example-2 parts of zinciodidewere dissolvedin .75

partsof water. [Under vigorous agitation 50 parts of. pseudo'-ionone were added and the mixturev was quickly heated to reflux temperature, There-f Byfracaction was analogous to that described inExam- I was replacedgbyf zinc'chloride."Isofnterization was 'arnples' were given-merely for-purposesof illusupon the scope of the present invention: This'invention-is susceptible ofconsiderable:"variation' and; modification the manner of its practical bromide or zinc iodideor a mixture of-ithe. two

flu wide a I 1 1 'V'Experirnents hare/ ndicated that thenlsornerie. za'tion reactions described hereinirequirelthe use: of specific agents, and cannotibe predicatedupon' nesiurn chloride, and cupric 'chloride,-having.ca

obtained thereby. r

zation took place more slowly due to the presplies 1,,2Qand 3, the crude'oon'den'sation products proportions of theindividualhalides. 1 .While zinc fluoride causes-- some isorner'ization;

rig: to; the results obtained'with the other ha-:

a i V f ,9 0,116 I pie, 1, an excellent yield of iono-ne having high purity being obtained. 7 Y I Example 3 v g One-half the zinc bromide .iused'in Example 1 L r with the lcoircentratlon Jot the iis'omerizing agent or agents; the preferred timebeingthat wherein elfected by the mixture of zinc bromide zinc reaction product chloride; and the pure ionohe isolatedaccording the refractive index of the to the'directionsof Example 1. The"resultsQwre- -reaches a ence of the zinc chloride. inethyl-dlkyli-ketonefsandcitral or oil of lemon- Emmlee i1'ect.iorrit 1s to be understood that where men- The pseudoionone usedin the aforementioned examples was replaced byen-i-equa1 'amo11nt iOfi pseudo-methyl-ionone, The procedure "described 7 in these examples was then-followed, resulting .infl Purification of the resulting products may be the production of. a good yield of methyl i'olione readily accomplished according to well known of excellentpurity..;. I H p 7 den-reduced pressure.-

In place or the.pseudo ionoheused.inEggarn- ,,1; b isqme rizeglfjw ith".a-frelatively inexpensive: r v r ag nt.--:=,"I he use otexp sf veeqtfipm ntr ndrth of acetone with oil' -oi lemongrass or citralere used.- Here again the results'wer finitesatisfactory, being comparable with those produced in the aforementioned ka'mplesii L J It is to be understood that the foregoing exisomerization 10f fresh qrmateriala .Needless: "to:

tration and wereinot intended as a limitation centrationof .zinfc halides mayfbewariedIwithinw large-scale m t rather" wide limitaalthoughthe most 'satisfac-. tory -resu1tsare-5ih general obtained b'y using a e t ve y:co tra e lu of the partin fir -the. spirit and :scope' thereof; itis tothe-speoific embodiments. thereof fined:inthejappendedclaimsu g I scribed; may be usedwith: excellent results. "Furthermore, these mixtures may containivarying thegresults obtained therewith' are. greatly ii'nfegives considerably ;lo'ett .v S' hn' coma obtained b cttheuse 9f eithr zincvchloride o z n leastztwotmemberseselected. rrom sisting o i the usual chemical ptheories; Chemical theory V V 'WALTER CHRIS'HAN LEULYE 51.111113! D I r n W retestedand egative results. g r

7 grass as-initlal components herein. In this con-'1 V tlon'is made in the specification and claims to 1.. In-th'e process of producingrionones.byfthe. isomerizationcof ps'oudo-ionones; the step which, comprisesitreatingyat eleyated=temperatures the; D eudo'ekSDone-with an adueolls'i'soliition ofea? I lides.- Zinc chloridegivessatisfactory results,:but;. ymlembenselected fromthe'gnou on j tingnfzmcj suchresults-arenot as satisfactory as'fwhemzihc; l r bromide-and/orjzinc iodide,isaddedjto thezinc, 2. ln -thermms of .producmg yignmes by chloride l e of i 1 9i '.isomerizationiof pseudoeiononesgtho stepcwhich 7 comprises treating at, elevated ttemperatunes the f .pseudo.-fionone.zvitl-ri*an aqueousxsolution'gofzat .55.; viodide, zinc bromldeeiandvzihc;

group'consisting 'oi zinciodideand zinc'bromidefi I l v p Y 4zfxThe process of"claimlit whereinthe pseudo H er sa -a m te i m 0 -11iononeuisirefluiiedjwithian aqueous solution '01;

-6 ride, 'mono-sodiumephosphate,yammoriiumzchlo The. temperatures employed may be varied withr inwide limits, but since the rate of reaction. drops with a decrease in temperature-it is ad visable to maintain the temperature at the ap-' proximate boiling point of the aqueous zinc salt solution. The time of reaction; likewise varies th aforementioned crude reaction products.

20' l V methods, for example fractionaljdistillation un- The present inventionperrnits pseudo-ionones 26 ne e t .Qic ed Owextractions' .or; dilutions; and r reconcentrationsiisentirely obviated-.ji'l'tieprom; "1 V are -separatedj;fr0m the isomerizing; 7 agent; and the latterma'y again be'jused for the? V 30. say thisl-results in a tremendous saving; High- 7 v yields of products hailing-excellent purity iare product-Ml. The progressgof thez isomerization is v readily controlled; and 'since :the,conditionsx-rnay5.. I V V be variedrwithinawlde ,limitsfwithoutimpairing appli at onr' a c t quantity and c n there st lts, thei'nventioniis particularlyiapplicai VAs manyep rently widely difierentabout ments or thisinvent-ion may be made withoutde-l V 40 m zin if"- 0f 'tWO to be-understoodthat the-invention'is' not limited r I or'more or theisomerizing agents heretofore'det. g

"'53; Inithe processiot produclngfiinbriesivbyithe-g isomerizationtot'qpseudo-ionones; ithe step; which p comprises refluxing thepseudo-iorrom withhn 'Qm'd iordmal'ilr Suggesflhafl cflmpounds .aclueio'us:soltitton 1011a" member selectedfrom-the: r icallyrelated -to the zinc halideswouldialso-evie;

f dence isomerizing abilitiesin gthis. coniiection..

. i l f 4 quite r, l h i W nQtfidrthat isogneri' f; Im -place lithe-pure pseudo-ionones, it is pos- I V sible to utilize the crude reaction products of 

